Drying apparatus for a wrinkled paper web

ABSTRACT

A wire loop is arranged to support a paper web which has been wrinkled in a damp condition and to carry the web through a drying zone. The wire is guided by rollers rotatably mounted in a frame on a base. Attached to the frame there are also blowing boxes sequentially arranged on one or both sides of the wire for blowing a hot gaseous medium like hot air on the wrinkled web during the drying operation.

lJnited States Patent [191 Ramala [451 Dec.3, 1974 DRYING APPARATUS FOR A WRINKLED PAPER WEB [75] Inventor: Pekka Paivio Rantala, Briarcliff Manor N [73] Assignee: A. Ahlstrom Osakeyhtio,

' Noormarkku, Finland [22] Filed: Oct. 20, 1970 I 21] Appl. No,: 82,329

[52] US. Cl. 34/155 [51] Int. Cl. F26b 13/00 [58] Field of Search 34/155, 158, 160, 162, 34/159, 23

[56] References Cited UNITED STATES PATENTS 1,741,755 12/1929 Chase et a1. 34/162 X 3/1959 Vander Pyl 34/23 LM LAMJ LHJ LH 3,254,426 6/1966 Lamb et al 34/160 X 3,314,162 4/1967 Haywood 34/155 3,371,427 3/1968 Thygeson i 34/155 3,418,727 12/1968 Morris 34/162 3,550,286 12/1970 Kontiinen 34/162 Primary Examiner-Carroll B. Dority, Jr. Attorney, Agent, or Firm-Br0oks, Haidt & l-laffner [57 ABSTRACT A wire loop is arranged to support a paper web which has been wrinkled in a damp condition and to carry the web through a drying zone. The wire is guided by rollers rotatably mounted in a frame on a base. Attached to the frame there are also blowing boxes sequentially arranged on one or both sides of the wire for blowing a hot gaseous medium like hot air on the wrinkled web during the drying operation.

1 Claim, 3 Drawing Figures PATENTEL [1E5 3 I974 Fig. 3

I'llllllll'il'llllllllnln'l 1 5 EAJ FOR A WRINKLED PAPER BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates .to the field of paper machine drying apparatuses, especially for drying a wrinkled paper web.

2. Description of the Prior Art The most common process for the manufacture of wrinkled paper is the process in which the paper track is wrinkled by aYankee cylinder. One disadvantage of this process is its weakening influence on the strength of the paper when the dry and fragile track is wrinkled. At this time most of the already formed fibre bonds break and consequently the strength of the wrinkled and the bonds between the fibres stay unbroken andv paper is greatly reduced. In addition this method requires drying cylinders with a great diameter, which are expensive and difficult to manufacture and transport.

The purpose of this invention is to provide an apparatus for the drying of a fibre web, particularly a wrinkled paper web, eliminating the disadvantages mentioned above.

SUMMARY or THEINVENTION According to the invention there is provided a new and useful apparatus for drying a paper web which has been wrinkled in a damp condition and having a base, a frame on the base,' rollers rotatably mounted in the frame, one or more moving endless wires guided by the rollers for supporting the paper web, and means attached to the frame for blowing a hot gaseous medium like air on the web in order to dry and press it against the wire whereby the wrinkles of the web are retained BRIEF DESCRIPTION or THE DRAWINGS FIG. 1 is a schematic side view of a paper machine with one advantageous embodiment of the drying device according to the invention,

FIG. 2 is a partial view (the encircled area, of area A, in FIG. 1) of the application shown in FIG. 1, on an enlarged scale, and

FIG. 3 is a similar view as FIG. 2, but of another embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus according to the invention is particularly suitable for the manufacture of wrinkled paper, in

'which case the paper track is wrinkled while it is relatively damp so that the fibres are still springy and unbonded and will not fracture under the influence of the wrinkling treatment. After this treatment the drying is carried out with an apparatus according to the invention; the fibre web is pressed tightly against the wire moving through the drying zone with the help of blowplication,.the outside pressure is greater than the inside i ing boxes that blow hot air on the paper track. The

wrinkles will not even out during this process because the differenceof pressure between the two sides of the wire is so great that the paper track is pressed tightly against the wire. Thus, no mechanical strain is directed to the paper web before it is dry. Therefore the fibres the result is a strong wrinkled paper web.

Dewatering may be made more effective by fitting dewatering wings on the opposite side of the wire in relation to the fibre track.

In an apparatus according to the invention, blowing boxes have been fitted either in the immediate vicinity of the web on the same side of the wire as the fiber web or on both sides of the web in its immediate vicinity. However, the blowing boxes placed on the same side of the wire as the fibre web direct a greater stress on the fibre web than the blowing boxes fitted on the opposite side of the wire so that a sufficient difference of pressure prevails between the two sides to press the fibre web tightly against the wire. Between the blowing boxes placed one after the other on one or both sides of the wire there are advantageously'outlets for the removal of humid air from the vicinity of the fibre track and for directing it away from the apparatus.

The wire is advantageously an endless loop fitted on guide rollers, of which at least one is perforated and machine head box, 2 to the wire part, 3 to the picking up roller, 4 and 5 to the pressing rollers and 6 to the wrinkling scraper. The operation and structure of these devices is not described in more detail in this connection because they may be of any known type. Numerals 7 and 8 refer to the paper guide rollers with which the wrinkled damp paper track 9 is fed into the drying device according to the invention.' In the drying device, numeral 10 refers to the wire loop, 1 l to the wire guide rollers, and 12 to the hood.

In the application shown in FIG. 2, several blowing boxes 13 have been fitted one after the other on the same side of the wire 10 as the paper web 9. The blowing boxes l3'blow hot air on the paper web 9 and press it tightly against the wire 10. The hot air heats the paper web 9, at which time the water contained in it vaporizes and is removed with the hot air to the perforated wire guide roller 11, which has a centered outlet for humid air. To make the steam deflecting more effective, stationary dewatering wings 14 have been fitted in the immediate vicinity of the wire on the opposite side of the wire 10 in relation to the paper web 9. The dewatering wings I4 cause changes of pressure along the wire 10 when it moves and thus make the evaporation more effective.

As can be seen from FIG. 3, hot air can be also blown with blowing boxes 15 fitted inside the wire loop 10. The air and evaporated water both from the space outside the wire loop 10 and from inside it are removed between the successive blowing boxes 15. Also in this ap' pressure in order to press the paper web against the wire 10.

The device according to the invention is suitable for the drying of different kinds of webs, particularly wrinkled paper tracks. The length of the wire depends on the amount of water to be evaporated and on the speed of the web. If necessary, several drying units may be linked one after the other, in which case each unit may have its own wire or all units may share a wire.

Hot air can be replaced with some other suitable gas which has a sufficiently high temperature, and radiator dryers can be used instead of the blowing boxes for the heating and drying of the damp paper web.

What is claimed is:

1. In a paper machine, a drying apparatus for a paper web which has been wrinkled in a damp condition,

the inside of the wire loop. 

1. In a paper machine, a drying apparatus for a paper web which has been wrinkled in a damp condition, comprising: a base; a frame on the base; rollers rotatably mounted on the frame; at least one moving endless wire guided by the rollers for supporting the wrinkled paper web; and means attached to the frame for blowing a hot gaseous medium on the wrinkled paper web on the wire in order to dry and press the web against the wire so that the wrinkles of the paper web are retained during the drying operation, at least one of the wire guiding rollers having perforations and an outlet connected to its inside to remove humid air from the inside of the wire loop. 